// trim: 清除字符串两侧空白
// trimStart: 清除字符串左侧空白
// trimEnd: 清除字符串右侧空白

let str = "   i love you    ";

console.log("清除字符串两侧空白", str.trim());
console.log("清除字符串左侧空白", str.trimStart());
console.log("清除字符串右侧空白", str.trimEnd());